Pole-number-changing rotary electric machine and driving method for pole-number-changing rotary electric machine

A driving method for a pole-number-changing rotary electric machine comprising:

• a rotary electric machine provided with a stator in which stator slots are arranged at regular intervals in a mechanical angle direction and a rotor rotated by magnetomotive forces generated by a current flowing through stator coils housed in the stator slots;
• an n-group inverter for supplying an m-phase current to the stator coils;
• and
• a control unit for controlling the n-group inverter,
• each of the magnetomotive forces corresponding to the stator slots being arranged at regular intervals, and a number of poles in the pole-number-changing rotary electric machine being changed between a time of high polarity driving and a time of low polarity driving, wherein
• the control unit includes a current supply step in which an m-phase current is supplied to the stator coils by the n-group inverter, and
• in the current supply step
• at the time of low polarity driving, current phases of the current flowing through the stator coils are controlled such that a current phase degree of freedom, which is a number of current phases per pole pair controllable by the n-group inverter, is equal to a number of groups n×a number of phases m, where the number of groups n is a multiple of 4 and the number of phases m is a natural number of 3 or more and relatively prime to the number of groups n, and
• at the time of high polarity driving, the current phases of the current flowing into the stator coils are changed such that the current phase degree of freedom is equal to the number of groups n×the number of phases m/2.